Users Guide

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Neighbor Discovery Protocol (NDP)
The neighbor discovery protocol for IPv6 is dened in RFC 2461 as part of the Stateless Address Autoconguration protocol. It
replaces the Address Resolution Protocol used with IPv4. NDP denes mechanisms for solving the following problems:
• Router discovery: Hosts can locate routers residing on a link
• Prex discovery: Hosts can discover address prexes for the link
• Parameter discovery
• Address autoconguration — conguration of addresses for an interface
• Address resolution — mapping from IP address to link-layer address
• Next-hop determination
• Neighbor unreachability detection (NUD): Determine that a neighbor is no longer reachable on the link.
• Duplicate address detection (DAD): Allow a node to check whether a proposed address is already in use.
• Redirect: The router can inform a node about a better rst-hop.
NDP uses the following ve ICMPv6 packet types in its implementation:
• Router Solicitation
• Router Advertisement
• Neighbor Solicitation
• Neighbor Advertisement
• Redirect
clear ipv6 neighbors
Delete all entries in the IPv6 neighbor discovery cache or neighbors of a specic interface. Static entries are not removed using this
command.
S4820T
Syntax
clear ipv6 neighbors [vrf vrf-name] [ipv6-address | interface]
Parameters
vrf vrf-name (OPTIONAL) Enter the keyword vrf followed by the name of the VRF to clear the
neighbor corresponding to that VRF.
NOTE: If you do not specify this option, the neighbors in the default VRF
are cleared.
ipv6-address Enter the IPv6 address of the neighbor in the x:x:x:x::x format to remove a specic
IPv6 neighbor.
NOTE: The :: notation species successive hexadecimal elds of zero.
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Neighbor Discovery Protocol (NDP)